I have a X540-T1 running in Windows Server 2012 R2.
I have updated drivers but never the flash.
Does updating the flash on this card help, or in other words is a driver update alone sufficient for this card?
I have not run across any write-up saying what the flash does in a situation where you are not using it for a network boot, but I do see the EFI version number on the card and my server motherboard is EFI based.
Updating the driver is sufficient for this card, the driver for the NIC is available at Intel® Download Center (Latest PROSEt version is 20.2 contining the driver ).
With regards to EFI, here is the driver link for Intel® Ethernet Connections Boot Utility, Preboot images, and EFI Drivers Intel® Download Center
Hope this helps.